Folic acid
Folic acid, or rather folates , are water-soluble vitamins whose biologically active form is represented by tetrahydrofolic acid (THF).
Folic acid is found above all in offal and in some foods of vegetable origin (of these, especially in beans , tomatoes and oranges ). Some studies (carried out in different areas of the national territory) have highlighted the collective tendency to take insufficient quantities of folic acid; this condition, in itself disadvantageous, significantly worsens in the elderlyand especially in men: deficiency estimated at 12% in women and 20% in men.
Folic acid is thermolabile; it is absorbed in the intestinal portion of the jejunum and mainly actively ( via a carrier) at pH 6, but also passively at higher pH. The metabolic function of folic acid is to originate coenzymes useful for the transport of single carbon units in the metabolism of amino acids and in the synthesis of nucleic acids , biochemically interacting with cobalamin (vit. B12) ; in a nutshell, folic acid participates in the production of nucleic acids ( DNA and RNA- whose defect causes anemia), the transformation of homocysteine into methionine and the metabolism of other amino acids .
It can be deduced that the reduction of the metabolic activity of folic acid can cause various decompensations, among which the most relevant is undoubtedly the reduction of the synthesis of DNA and RNA; due to the reduced ability to replace “old” or damaged cells with “new” cells, tissues that need more frequent turnover (cell turnover) are subjected to functional alterationsof a serious nature. This condition has a heavy impact on the nervous tissue and in particular on the development of the spinal cord of the fetus ( spina bifida ) and on the cerebral degeneration of the elderly; moreover, the reduced ability to synthesize nucleic acids also significantly affects bone marrow erythropoiesis ( the production of red blood cells) causing or aggravating anemia . The recommended intake of folic acid is 200 µg/day, an amount that doubles for pregnant women (in order to prevent neural complications of the newborn
). Some studies carried out on malnourished patients have demonstrated good collective tolerance even at doses that reach 5mg/day, albeit with the risk of concealing the deficiency manifestations from cobalamin insufficiency (vit. B12) .
Folic acid deficiency anemia
Anemia is one of the reflex complications attributable to the reduced metabolic function of folic acid and / or cobalamin (vit. B12). Such a condition can arise for several reasons:
- Folic acid dietary deficiency : as anticipated, folic acid is contained both in offal and in foods of vegetable origin. It is true that it is a heat-sensitive vitamin, therefore, it can be deduced that its integrity is lost when the food is cooked . Therefore, the contributions deriving from cooked offal or stewed legumes should not be fully considered , while the folates deriving from raw vegetables should be more complete; a final consideration should be made regarding the bioavailability of folic acid in foods. Some studies on the absorption capacity of folic acid have shown that VEGETABLE foodsthey also contain chelating molecules capable of hindering the uptake of these vitamins ; for example, beans have a bioavailability of folates that reaches 80% while oranges only have 20%. To ensure the minimum amount of folate and avoid the onset of anemia, it is recommended to consume RAW foods of vegetable origin on a daily basis.
- Alteration of folic acid absorption : it is generally rare but frequent in patients subjected to surgical resections of one or more parts of the digestive tract , who often show anemia.
- Use of drugs that hinder the metabolism of folic acid : some molecules such as methotrexate , barbiturates and contraceptives are responsible for the metabolic alteration involving folic acid. In the case of a similar pharmacological therapy, the subject must take greater care of the nutritional intake of folates in order to prevent the onset of anemia.
Symptoms
Anemia caused by the ineffectiveness of folic acid is characterized by the medullary production of NOT mature, larger, more colored and less efficient erythrocytes .
The characteristic symptoms of this anemia are superimposable and often concomitant with those of cobalamin deficiency; in addition to the generalized tiredness typical of all anemic forms, there is an involvement of the gastrointestinal system (presence of anti-mucosal antibodies ) but above all of the nervous system, through the manifestation of numbness, absence of reflexes and lack of motor coordination .
Wanting to classify folic acid deficiency anemia, one could define that:
while making an appropriate distinction of the etiological cause , it is a set of symptoms and clinical manifestations that can be superimposed on pernicious and/or megaloblastic anemia . In fact, folic acid acts synergistically with cobalamin in the synthesis of nucleic acids and therefore the deficiency of one, the other or both often favors the appearance of an almost analogous clinical picture.
